Powertrain controls

ABSTRACT

Systems, methods, and computer-readable storage media directed toward reducing emissions are disclosed. In some aspects, a hybrid powertrain may include an engine and a motor. A combination of output from the engine and motor may be chosen that reduces a concentration of one or more pollutants. In some cases, an exhaust aftertreatment system may be remotely activated, which may reduce warmup time associated with emissions mitigation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of U.S. provisional patentapplication No. 61/220,200, filed Jun. 25, 2009 and entitled “PowertrainControls,” which is incorporated by reference herein.

BACKGROUND

1. Technical Field

The present invention relates generally to reducing the impact ofemissions from engines, turbines, boilers, furnaces, and the like.

2. Description of Related Art

Engines, turbines, boilers, furnaces, and the like typically createemissions streams resulting from combustion. Reducing the local and/orglobal impact of combustion may require the mitigation (e.g., reductionand/or elimination) of one or more emitted species from the emissionsstream.

Emissions streams may include “criteria pollutants” and/or pollutantssuch as particulate matter (soot), nitrogen oxides (NOx), carbonmonoxide (CO), hydrocarbons, and the like. Emissions streams may includeglobal warming pollutants (e.g., CO2). Some species (e.g., soot, NOx)may be criteria pollutants and global warming pollutants.

Some existing hybrid powertrains combine an electric motor and anengine. In some configurations, the motor and engine may operatedtogether in an effort to minimize fuel consumption. However, someapplications may require minimization of pollutants (e.g., pollutantsother than CO2).

The relative impact of one pollutant vs. another may vary as a functionof location (e.g., urban vs. countryside), time (rush hour vs. latenight), time of year, and the like. For example, the respiratory healthof a worker at a toll booth may be more impacted by criteria pollutantsthan CO2 emissions. Minimizing an integrated or overall impact of anemissions stream may provide for improved local, regional, and globalhealth. An ability to “change the mix” of emitted species might reducethe impact of a powertrain.

SUMMARY OF THE INVENTION

Various aspects provide for reducing emissions from exhaust streams. Apowertrain may comprise an engine and control circuitry, and may beconfigured to fulfill a demand for output associated with a load on thepowertrain. In some cases, a powertrain includes a motor coupled to atleast one of the engine and the load. The engine and motor may becoupled (e.g., with a clutch). Certain embodiments include an onboardenergy supply (e.g., a fuel tank, a battery, an ultracapacitor, a solarcell, and the like). Some embodiments may be attached to line power(e.g., an electrical grid) and/or a gas line (e.g., a natural gas line).

A method for operating a powertrain may include receiving a demand foroutput. A first emissions profile associated with fulfilling the demandunder a first operating condition may be determined, predicted, and/orcalculated. The first emissions profile may characterize one or morepollutants in an exhaust stream emitted from the engine during operationaccording to the first operating condition. A second operating conditionmay be determined, which may be associated with a second predictedemissions profile. The second emissions profile may have a reducedconcentration of at least one pollutant as compared to the firstemissions profile. The demand may be fulfilled according to the secondoperating condition.

In some cases, the reduced pollutant may be at least one of soot (orBlack Carbon, particulate matter, and the like), NOx, CO, and CO2. Insome cases the second emissions profile may have an increased amount ofone pollutant (as compared to the first emissions profile) and have areduced amount of another pollutant. In certain embodiments, the secondprofile may have an increased amount of CO2 as compared to the firstprofile and a reduced amount of at least one of soot and NOx as comparedto the first profile.

In some embodiments, a demand for output is fulfilled with combinationof output from a motor and an engine. In some combinations, an overalland/or integrated impact of an emissions stream is reduced by reducing aconcentration of a first pollutant. In certain cases, emission of a lessharmful pollutant may be increased in order to decrease an emittedamount of a more harmful pollutant. Some embodiments incorporatelocation, time, and/or duty cycle information in the minimization ofenvironmental impact. In some aspects, a pollutant having a highertoxicity (e.g., soot) is reduced in locations of higher populationand/or closer proximity to the emission.

A method of operating a powertrain may include activating anaftertreatment system associated with the powertrain in concert with thereceipt of a demand for output from the powertrain. Activation mayinclude heating the aftertreatment system, injecting a substance intothe activation system, and/or otherwise preparing or preconditioning theaftertreatment system. In some cases, an aftertreatment system may beactivated prior to a demand for output. In some cases, the demand foroutput activates the aftertreatment system. In some embodiments, apowertrain may include an energy supply (e.g., a battery), an engine, agenerator, and an aftertreatment system. The battery may activate theaftertreatment system, and may be recharged by the generator. In somecases, an initial demand for output from a cold powertrain may befulfilled by the battery (e.g., while the aftertreatment system warmsup). Upon sufficient activation of the aftertreatment system, the enginemay be activated. The engine may fulfill the demand for output and/orrecharge the battery.

A system for reducing a concentration of a pollutant in an exhauststream may provide for “remote” exhaust mitigation (e.g., of an enginehaving otherwise “unmitigated” or less mitigated emissions). A systemmay include an aftertreatment device including a container having aninlet and an outlet, and a substrate within the container, disposed tointeract with an exhaust stream passing between the inlet and theoutlet. The substrate may have chemical and/or physical properties(e.g., porosity, composition, adsorptive, absorptive, catalytic,crystallographic, and/or other properties) that reduce the concentrationof a pollutant in a gas stream interacting with the substrate. A hosemay have a first end attached to the inlet of the container. The hosemay have a second end configured to be disposed near and/or attach to atailpipe emitting an exhaust stream (or otherwise “gather” the exhauststream). In some embodiments, the hose may include a fitting toremovably attach to a tailpipe. The system may include a suction device(e.g., a fan, a pump, bellows, and the like) configured to draw gases(e.g., the exhaust stream) into the aftertreatment system. In somecases, the suction device may be disposed at the outlet. The system mayinclude a heater, which may be configured to increase the temperature ofcomponents interacting with the exhaust stream. In some embodiments, thesubstrate may include a particulate filter, a NOx trap, a lean-NOxcatalyst, and/or an SCR system. A heater may be disposed in a mannerthat heats the substrate, which may provide an “early warmup” of thesubstrate. The heater may be disposed in a manner that alters gas flowthrough the substrate (e.g., disposed in a region of a filter thatpreferentially clogs with soot, or disposed in a region that tends to bethe “last region to clog” with soot).

Certain embodiments include wired and/or wireless communications. Insome cases, an aftertreatment system may receive an activation commandfrom a remote device. A remote device may be associated with a user(e.g., a person testing a backup generator, a driver of an ambulance,and the like). A remote device may include an automated device (e.g.,coupled to a GPS system) that notifies the aftertreatment system whenthe engine is within a certain distance of the system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-C illustrates several exemplary representations of emissionsrelationships as a function of operating conditions (hereinafter: maps).

FIGS. 2A and 2B illustrate two exemplary illustrations of “duty cycle”characteristics.

FIGS. 3A and 3B illustrate exemplary demands for output that may resultin an increase in emissions.

FIG. 4 illustrates an exemplary deconvolution of demand, according tosome embodiments.

FIG. 5 illustrates various aspects of a hybrid powertrain, according tocertain embodiments.

FIG. 6 illustrates several components of a control device, according tosome embodiments.

FIG. 7 illustrates a method, according to some embodiments.

FIG. 8 illustrates a method, according to some embodiments.

FIG. 9 illustrates a method, according to some embodiments.

FIG. 10 illustrates an exemplary system, according to some embodiments.

FIG. 11 illustrates an exemplary system, according to some embodiments.

DETAILED DESCRIPTION OF THE INVENTION

Various aspects provide for treating an emissions stream to reduce aconcentration of one or more species. An overall and/or integratedimpact of an emissions stream may be reduced by controlling and/orotherwise varying a temporal dependence of the ratio of certain speciesto other species.

A powertrain may include a device to convert chemical energy to workand/or heat (e.g, a direct injection engine, a spark induced ignitionengine, a gasoline engine, a diesel engine, a natural gas engine, anethanol engine, an HCCI engine, a stratified charge engine, a turbine, astirling cycle engine, a boiler, a furnace, a fluidized bed combustor, aboxer engine, an opposed piston engine, an opposed pistion opposedcylinder engine, a two cycle engine, a four cycle engine, an Otto cycleengine, an Atkinson cycle engine, and the like, hereinafter: engine). Ahybrid powertrain may be dynamically controlled to reduce emissions. Insome cases, dynamic control includes changing operating conditions ofthe engine to change a ratio of emitted pollutants (e.g., soot vs. NOx).A hybrid powertrain may include multiple fuel sources (e.g., a dieselengine may be coupled to a propane-fired heater).

In some embodiments, a hybrid powertrain includes an engine whoseoperating conditions may be changed in a manner that alters a ratio ofemitted species. In some configurations, an engine may be operated in a“high soot” mode for a first period of time, and operated in a “high NOxmode” for a second period of time. In some cases, NOx (e.g., NO2) may beused to oxidize soot. In some cases, soot may be used to reduce at leastone of N2O, NO, NO2, and the like.

A hybrid powertrain may include more than one motive force generator. Insome cases, an engine may be hybridized with an electric motor, andpower (to a load) may be provided by the engine and/or motor. A motormay receive power from a power cable (e.g., coupled to the electricalgrid). A motor may be coupled to an energy storage device (e.g., abattery, a flywheel, and the like).

The engine may include an emissions aftertreatment device, and mayexhaust heat and chemical species (e.g., soot (or particulate matter),NOx, hydrocarbons, CO, CO2) through the aftertreatment device. Theaftertreatment device may include a substrate, which may operate with orwithout a catalyst. In some cases, a catalyst may be injected (e.g.,into the engine, into the aftertreatment system, or elsewhere). Acatalyst may be disposed on the substrate (e.g., with a wash coat).

Various aspects may include sensors (e.g., pressure, temperature, flow,concentration of various chemical species, and the like). Anaftertreatment device may include a heater (e.g., a glow plug), that maybe electrical and/or fueled (e.g., with engine fuel, propane, gridpower, a battery, and the like). The heater may include an ignitor(e.g., a piezoelectric spark ignitor). The heater may be disposed in afirst region of the aftertreatment system such that the first region maywarm up more quickly than a second region. The heater may be disposed ina first region that might otherwise warm up more slowly than a secondregion. In some cases, a heater may be associated with a region throughwhich a larger percentage of an exhaust stream passes (e.g., a “highflow” region). In some cases, a heater may be associated with a “lowflow” or even a relatively “stagnant” region.

A powertrain control unit may be coupled to various components and mayreceive demands for power, torque, heat, and the like (hereinafter:output). A demand may be received from a user (e.g., using anaccelerator pedal). A demand may be received from one or more automatedcontrollers. A demand may be received from a load coupled to thepowertrain and/or powertrain control unit. A received demand for outputmay be used to calculate one or more operating conditions that couldprovide the demanded output. In some cases, calculation may includereceiving signals from one or more sensors (e.g., engine speed, vehiclespeed, time, and the like). Some embodiments may incorporate location invarious calculations. For example, a powertrain incorporating a dieselengine and an electric motor may be at least partially controlled basedon geographical location (e.g., using GPS coordinates and/or localnetworks). Such a powertrain may provide a larger amount of output fromthe electric motor when the powertrain is located near a hospital,nursing home, or school.

Calculation may include using a past operating history and/or apredicted future operation. One or more “recipes” for demand fulfillmentmay be calculated, and a recipe that minimizes one or more pollutantsmay be chosen. For example, a heavy truck accelerating away from a tollbooth may be associated with a demand for maximum torque. A firstoperating condition that fulfills this demand may result in substantialsoot or NOx emissions (e.g., in the vicinity of the toll booth). Asecond recipe for demand fulfillment may include the provision of torquefrom an onboard battery and electric motor. The second recipe mayinclude reduced demand for torque from the engine, which may result inreduced soot emissions. Certain embodiments may provide for reducedemission of criteria pollutants, even though the emission of otherspecies (e.g., CO2) might be increased.

FIGS. 1A-C illustrates several exemplary representations of emissionsrelationships as a function of operating conditions (hereinafter: maps).FIGS. 1A-C schematically represent relationships involving twopollutants—soot and NOx—although similar maps may be generated withrespect to CO, CO2, hydrocarbons, NH3, and/or other species.

FIG. 1A illustrates a schematic map of emissions concentration as afunction of engine operating conditions. In this example, differentoperating conditions may result in a range of combinations of flametemperature and equivalence ratio. A first operating condition 110 mayresult in relatively high concentrations of soot in the emissionsstream. A second operating condition 120 may result in relatively highconcentrations of NOx in the emissions stream. A third operatingcondition 130 may result in relatively lower concentrations of soot andNOx.

FIG. 1B illustrates a schematic map of emissions concentration as afunction of engine operating conditions. A first combination 112 ofBrake Mean Effective Pressure (BMEP) and engine speed (and/or power) mayresult in increased soot emissions. A second combination 122 of BMEP andengine speed may result in increased NOx emissions. A third combination132 may result in reduced emissions of soot and NOx. FIG. 1C illustratesan exemplary “emissions tradeoff” curve. A typical powertrain may becharacterized by a first combination of emitted soot and NOx. In somecases, a first curve may describe a relative amount of emitted sootand/or NOx—creating a “tradeoff” in emissions reductions—at a givenload, the engine either emits more soot or more NOx. A hybrid powertrainmay be operated at a second condition 160 to result in the reduction ofmultiple pollutants (e.g., soot and NOx).

Knowledge of a map associated with an engine may be used to determineemissions as a function of different demands for output. In some cases,a demand for output may be received. A predicted emissions stream basedon a first set of operating conditions may be calculated (e.g., a firstposition on an engine map). A combination of motive forces (e.g.,electric motor and engine) may be determined that results in engineoperating conditions (e.g., a second position on the engine map) thatyields an improved emissions stream.

Some engines emit high quantities of pollutants under conditions nearmaximum output. Certain embodiments use a supplementary motive force(e.g. an electric motor) to provide a torque boost and/or power boost toan engine, such that peak emissions are reduced. For some applications,knowledge about (e.g., sensing of, history of, prediction of) a dutycycle may be used to reduce emissions.

FIGS. 2A and 2B illustrate two exemplary illustrations of “duty cycle”characteristics. FIG. 2A illustrates a backhoe 200, which may include anengine (e.g., a diesel engine, not shown) to fulfill load demands. Loaddemands may include operating tracks 210 to move the backhoe, rotatingthe shovel/cabin structure (e.g., about axis 220), operation of shovel230, HVAC (e.g., inside the cabin) and the like. Loads may operate overdifferent time scales with different output requirements. For example,tracks 210 may be operated relatively infrequently as compared to shovel230. FIG. 2B illustrates a schematic of a crane 240, which may includean engine (and may include more than one engine). Crane 240 may lift anobject 250 (e.g., steel girders, a shipping container, and the like). Insome cases, the functional nature of a device incorporating a powertrainprovides information regarding the duty cycle—a backhoe is typicallyused to dig holes, a crane typically lifts objects, a bulldozertypically pushes earth.

Certain demands for load may be characterized by a characteristicdependency of load vs. time (e.g., a periodicity, a time between tests,and the like). For example, backhoe 250 may scoop earth with shovel 230during a “high load” period “A” and return to a position to take anotherscoop during a “low load” period “B.” Crane 240 may lift object 250 fromthe ground during a “high load” period A and return (e.g., to theground) during a “low load” period B. Certain embodiments may providefor reducing total emissions by increasing engine output during “lowload” conditions (e.g., charging a battery) such that a reduced engineoutput is necessary during “high load” conditions. In some embodiments,a battery, capacitor, flywheel, and/or other storage device may be“charged” during low load conditions (marginally increasing relativeengine demand) and discharged during “high load” conditions (providingfor reduced emissions). In some applications using standard powertrains,short periods of time may result in relatively large pollutantemissions. A hybrid powertrain may provide for a “peak shaving” effectwith respect to emissions by “smoothing” the output demands on theengine.

FIGS. 3A and 3B illustrate exemplary demands for output that may resultin an increase in emissions. FIG. 3A schematically illustrates ahypothetical plot of demand vs. time that may be representative of atransit vehicle. During motion (e.g., carrying passengers), output maybe relatively high. Stopped (e.g., at a bus station), the engine may beidling. Highest output may be required during acceleration (e.g., awayfrom a train station). In some cases, high demand (which might beassociated with high emissions from a standard powertrain) may occurclose to large concentrations of people (e.g., people waiting at a busstop). For some pollutants (e.g., soot), there may be a strongdependency on toxicity of exposure vs. concentration. As a result,emitting pollutants within a few feet of a person may be much moredangerous than emitting those pollutants tens of yard or hundreds ofyards away. Certain embodiments provide for reducing a short-term“spike” in emissions by using a hybrid powertrain that calculates arecipe that meets a demand at reduced emissions.

FIG. 3B illustrates an exemplary schematic “cold start” spike associatedwith emissions. In typical systems (e.g., a car with a catalyticconverter, a backup generator, and the like), an emissionsaftertreatment system may not fully function until exhaust heat has“warmed up” the aftertreatment device. In some cases, short-time-scaleemissions (during warmup) may be significantly larger than “steadystate” emissions associated with a normally functioning device.

An exemplary hybrid powertrain may include a diesel, natural gas,syngas, and/or gasoline engine, and may include an electric motor(optionally with an energy storage device such as a capacitor, battery,flow battery, and the like). A backup generator may have a duty cyclecomprising extended periods of time with no demand for load,interspersed with periods of high demand for load. Some times of highdemand may be predicted (e.g., a testing procedure for the backupgenerator). Some times of high demand may not be predicted (e.g., apower outage). In some cases, grid power may be used to reduce emissionsfrom a hybrid powertrain having an engine and motor (e.g., duringtesting). In some cases, an energy storage device may provide power thatenables the engine to reduce emissions (e.g., a battery or propane tankmay begin heating an aftertreatment device upon being triggered by apower outage).

In some applications, a priori knowledge of an incipient demand may beused to precondition (e.g., preheat) an emissions aftertreatment system(e.g., to prepare for a testing protocol). In some embodiments, awireless signal (e.g., from a cellular, 802.*, Bluetooth, or similarlyenabled device) may trigger activation of an emissions aftertreatmentsystem. In some cases, activation may include preheating, that mayinclude using electrical power. Grid power and/or a coupled energystorage device may provide energy for preconditioning, preheating, andthe like. In some cases, (e.g., an emergency backup), a coupled energystorage device may be used to quickly heat an emissions aftertreatmentsystem to improve catalytic activity, particulate matter filterlightoff, and the like. In some cases, knowledge of an historical dutycycle (e.g., number of times a system has been operated withoutlightoff) may be used to calculate a control protocol for an emissionsaftertreatment system.

A hybrid powertrain may incorporate an electrochemical cell and anengine. The electrochemical cell may provide power while the engineand/or aftertreatment system associated with the engine heats up. Theelectrochemical cell may be used to heat the exhaust stream and/oraftertreatment system (e.g., such that the aftertreatment system reachesan operation temperature sooner than if heated only using exhaustgases).

FIG. 4 illustrates an exemplary deconvolution of demand, according tosome embodiments. Integrated demand 400 may characterize a temporaldependence of the output demanded of a powertrain. Integrated demand 400may include periods of relatively higher output (A) and lower output(B). Integrated demand 400 may be deconvoluted into a plurality ofdemand components (in this example, demand components 410, 420, and430). Deconvolution may include transforming integrated demand 400(e.g., using Fourier and/or Laplace transforms). Deconvolution mayinclude monitoring sensors associated with various loads and associatingthese sensors with changes in integrated demand 400. Deconvolution mayinclude using maps associated with the powertrain. Emissions as afunction of demand may be measured, calculated, and/or predicted.Exemplary emissions response 440 may correspond to emissions emitted bya powertrain fulfilling integrated demand 400 under first operatingconditions. Emissions response 440 may be associated with one or moreemitted species, and may be deconvoluted temporally (as with integrateddemand 400) and/or chemically (with respect to emitted species).

In some embodiments, one or more demand components is associated with atleast a portion of emissions response 440. For example, demand component420 may be associated with a short term “spike” in emissions. A hybridpowertrain may include hardware (e.g., a battery and motor) sizedaccording to the requirements of demand component 420 (e.g., torque,power, energy, periodicity, and the like), and so may be operated topreferentially provide power in a manner that reduces overall emissionswhile meeting integrated demand 400.

Deconvolution of integrated demand and/or emissions may include theincorporation of duty-cycle information. Certain powertrains are used inapplications characterized by duty cycles having some repeatibility,predictability and/or periodicity. Knowledge about historical dutycycles and/or prediction of future duty cycles may be used to reduceemissions and/or improve the performance of emissions control systems.In some cases, an application toward which a powertrain is directed maybe used to determine duty cycle information. User input may be received(e.g., a projected use time). In some cases, duty cycle information maybe uploaded and/or downloaded (e.g., wirelessly). Duty cycle informationmay be calculated (e.g., by summing or integrating historical orpredicted use data). Duty cycle information may include locationinformation. For example, a tractor may be used to plow a field, and GPSinformation associated with the location of the tractor may be used todetermine a percentage of the field yet to be plowed, and by extension,an estimate of time to completion under a given set of load conditions.An estimate of time to completion may be used to determine (for example)whether or not to regenerate a soot filter, NOx trap, and the like. Dutycycle information may include fuel information (e.g., a percentage ofFAME in biodiesel, a percentage of ethanol in gasoline, a cetane, asulfur level, a viscosity, and the like). Duty cycle information mayinclude environmental information (e.g., temperature, weather,altitude). Duty cycle information may include an estimated time in port(e.g., for a ship), availability of hotel power, time at a truck stop,time until reaching a rest area, time until end of shift, and the like.

Some hybrid powertrains may have a finite amount of available energy(e.g., from a battery) with which to minimize environmental impact. Forexample, a mobile application may include an engine having 100 kW outputand a battery capable of storing 1 kW (with adequate lifetime). Usingthe available energy in the battery to reduce CO2 emissions from theengine may provide less benefit than using energy in the battery toreduce the emission of soot, NOx, hydrocarbons, and the like. A fewhundred watt-hours of energy might improve emissions more if directedtoward heating a (cold) aftertreatment system.

In some cases, a plurality of responses may characterize a duty cycle.For example, a diesel backhoe may have one response or modecharacterizing steady-state operation of the engine (e.g., low torqueloads) and another mode characterizing major torque requirements.

Some aspects provide for using knowledge of duty cycles (e.g., torquerequirements and/or time dependence of load(s)) to reduce emissions. Insome cases, an engine, motor, and storage device are coupled, and a dutycycle prediction and/or history may be used to determine a combinationof engine, motor and energy source applied to a load. Certain aspectsinclude using an energy storage device and/or other (non-combustion)energy source to provide at least a portion of demanded torque, whichmay allow operation of the engine in a less-polluting regime than mighthave been required without hybridization of the response to load.

FIG. 5 illustrates various aspects of a hybrid powertrain, according tocertain embodiments. A load 500 may require output from hybridpowertrain 510. A demand for output may be transmitted to the hybridpowertrain using a mechanical, electrical, optical, wireless, acoustic,and/or other signal mechanism (not shown). Hybrid powertrain 510 mayinclude an engine 530, which may optionally include control mechanismsconfigured to change the composition of an emitted exhaust stream.Exemplary mechanisms include control of injection timing, injectionduration, number of injections, fuel/air ratios, ignition timing,exhaust gas recirculation amount, boost, and the like. Certainembodiments may include an electric motor 540 (and/or generator,alternator, and the like). Some embodiments may not include a motor.Various components of hybrid powertrain 510 may be coupled to load 500via one or more clutches 520. In some embodiments, engine 530 is coupledto load 500. In some embodiments, motor 540 is coupled to load 500.Engine 530 and motor 540 may optionally be coupled together (e.g., witha clutch 520). In some embodiments (e.g., a serial configuration), oneof engine 530 and motor 540 is coupled to load 500. In some embodiments(e.g., a parallel configuration) both engine 530 and motor 540 arecoupled to load 500.

Motor 540 may receive power from a power line (e.g., grid power, aphotovoltaic cell, and the like). Motor 540 may receive power from anenergy storage device 550 (e.g., an electrochemical cell, flow battery,fuel cell, capacitor, ultracapacitor, Li-ion battery, and the like). Insome embodiments, energy storage device 550 includes a mechanism formechanically and/or chemically storing energy (e.g., a flywheel, acompressed gas canister, and the like), which may be mechanicallycoupled to motor 540 and/or engine 530 (e.g., with a clutch, valve,thermoelectric module, and/or other device to convey energy to/from thestorage device). In some cases, energy storage device 550 may be coupledto a generator (not shown) which may be coupled to motor 540. Motor 540may serve as a coupling between energy storage device 550 and othercomponents.

Engine 530 may be in fluid communication with an exhaust aftertreatmentsystem 560. Aftertreatment system 560 may receive exhaust gas fromengine 530 and treat the exhaust gas (e.g., in a manner that reduces theenvironmental impact of the exhaust gas). Aftertreatment system 560 mayinclude a catalytic converter (e.g., with a 2-way catalyst, 3-waycatalyst, and the like). Aftertreatment system 560 may include a dieseloxidation catalyst (DOC), a soot filter, a system to remove NOx, and thelike. A system to remove NOx may include a lean NOx trap. A system toremove NOx may include a selective catalytic reduction (SCR) system.Aftertreatment system 560 may include components as described in U.S.patent application Ser. Nos. 12/183,917, filed Jul. 31, 2008, and12/756,987, filed Apr. 8, 2010, the disclosures of which areincorporated by reference herein.

Some implementations may include an injector or other mechanism toinject species into an aftertreatment system. Fuel, urea, syngas, NH3,air, oxygen, AdBlue™, ethanol, esters, and/or other species may beinjected. Some species may be stored (e.g., in an energy storagedevice). Certain embodiments include apparatus for performing SCRreactions (e.g., within the aftertreatment system). Some species may beconverted into another species prior to injection. In the embodimentshown in FIG. 5, a reformer 564 may convert a stored fuel (e.g., dieselfuel, propane) to a species (e.g., syngas) and inject the species intoaftertreatment system 560. Devices (e.g., reformer 564) may be incommunication with and/or controlled by various other components (e.g.,PCU 590).

Some implementations may include a heater 562. Heater 562 may beconfigured to heat exhaust gas (e.g., directly), heat a component (e.g.,a tube carrying exhaust), heat a substrate (e.g., a substrate treatingthe exhaust), heat a container (e.g., a can containing a substrate) andthe like. Heater 562 may be configured to heat aftertreatment system560. Heater 562 may include an electrical heater (e.g., a heatingelement) which may be coupled to other components (e.g., energy storagedevice 550). Certain embodiments of hybrid powertrain 510 may includechemical storage of fuel (e.g., diesel fuel, urea, ammonia, methane,ethane, propane, butane, pentane, LPG, hydrogen, butanol, ethanol,methanol, propanol, esters, aldehydes, and the like). In some cases,heater 562 may be coupled to the chemical storage, which providesheating energy. In some embodiments, a propane tank delivers propane toheater 562. Heater 562 may include an ignitor (e.g., a spark plug) whichmay be coupled to various other electrical and/or energy storagecomponents. In some embodiments, energy storage device 550 includes abattery, and heater 562 includes a resistive heating element.

Some embodiments of hybrid powertrain 510 may include a turbocharger570. Some embodiments may include an exhaust gas recirculation system(EGR) 580. Turbocharger 570 and/or EGR 580 may be in fluidiccommunication with engine 530 (e.g., with the exhaust gas from engine530) and may be electrically and/or mechanically coupled to othercomponents (e.g., controlled by another component).

Various components of hybrid powertrain 510 may be controlled bypowertrain control unit (PCU) 590. PCU 590 may be in communication withone or more components described herein, and may include wired and/orwireless communication circuitry. PCU 590 may transmit and/or receivesignals associated with load 500, clutch(es) 520, motor 540, engine 530,energy storage device 550, aftertreatment 560, heater 562, turbocharger570, EGR 580, and/or other components. PCU 590 may be configured toreceive input from an operator (e.g., a driver of a vehicle) and/or anautomated or computer-controlled device. PCU 590 may be configured totransmit and/or receive cellular signals, 802.* signals, bluetoothsignals, GPS signals, and/or other signals.

FIG. 6 illustrates several components of a powertrain control unit,according to some embodiments. A processor 610 may be configured toexecute instructions stored on a computer-readable storage medium, suchas memory system 620 (e.g., hard drive, flash memory, RAM and the like).An energy storage interface 630 (and/or line power interface) mayinterface with an energy storage device and/or meter associated with thepower line. An engine control unit interface 640 may interface with anengine control unit (e.g., associated with engine 530). A motorinterface 650 may interface with a motor (e.g., motor 540). A loadinterface 660 may interface with a load and/or a sensor associated witha requested or demanded output. Sensors may include position sensors(e.g., of an accelerator position), torque sensors, piezoelectricsensors, optical sensors, magnetic sensors, thermocouples, flow sensors,pressure sensors, acoustic sensors, engine timing sensors, rotationsensors, and the like). Load interface 660 may be in wired, wireless,and/or other communication with load 500. Sensor interface 670 mayinterface with one or more sensors. A sensor may sense a characteristicof an engine, a motor, an energy storage device, temperature, mass flow,an aftertreatment device, an emissions stream (e.g., upstream and/ordownstream of an aftertreatment device), pressure, soot loading, NOx,CO, hydrocarbons, NH3, torque, power, and the like. In some embodiments,an aftertreatment interface 680 may interface to an aftertreatmentdevice (e.g., aftertreatment device 560 and/or heater 562). Variouscomponents may be coupled (e.g., via bus 690). PCU 590 may includeand/or be coupled to wired and/or wireless communications circuitry.

FIG. 7 illustrates a method, according to some embodiments. In step 710,a demand or request for output is received (e.g., at PCU 590). In step720, a predicted emissions profile associated with fulfilling therequest under a first operating condition (e.g., a “standard” and/or“suboptimal” operating condition) is calculated. In some cases, dutycycle information associated with the powertrain may be received, andmay be used in various calculations. In step 730, one or more secondconditions is determined (e.g., calculated using a minimizationalgorithm). A second condition may include a set of operating conditionsthat fulfills the request and is predicted to result in reducedemissions as compared to the first condition.

A second condition may include adjusting a heater temperature associatedwith an aftertreatment device. A second condition may include acombination of motive forces (e.g., engine and motor) that is differentthan that of the first condition. A second condition may include anadjustment in engine controls (e.g., injection timing) as compared tothe first condition. A second condition may include injecting a fueland/or reductant into an aftertreatment device. For a given set ofoperating parameters that describes an operating condition of a hybridpowertrain, a first condition may be a first set of values for theparameters and the second condition may be a set of values, for which atleast one parameter has a different value. In some embodiments, a firstset of values is received, an emissions profile according to the firstset is calculated, a first value is modified to become a second value,and a second emissions profile according to the second set iscalculated. Values may be modified randomly (e.g., changed by a fewpercent about the previous value). An emissions profile may be minimizedusing a minimization algorithm (e.g., least squares, Monte-Carlo, andthe like) in which permuted values that result in reduced emissions arepreferentially selected, subject to operational constraints (e.g.,fulfilling the demand).

In step 740, a second condition that fulfills the request at reducedemissions is chosen. The chosen condition may result from theminimization algorithm (e.g., be one of the minima in emissions thatfulfills the demand). In some aspects, the first condition includesoutput provided by an engine, and the second condition includes outputprovided by an engine and a motor. In some embodiments, the request isassociated with a demand for high (or maximum) torque, and the secondcondition provides for the demanded torque using the motor and/or acombination of engine and motor. In some cases, torque may be providedexclusively by the motor for a period of time that may be associatedwith capacity of an energy storage device coupled to the motor. Forexample, the first few seconds (e.g., first five seconds, three seconds,two seconds, one second or even 0.5 seconds) of high torque may beprovided by a motor connected to an ultracapacitor, which may allow theengine to operate in a condition that results in reduced emissions ascompared to the engine providing the requested torque for those fewseconds.

In an exemplary embodiment, a hybrid powertrain may include an engineand a battery, and may be configured for a “backup power” duty cycle. Ademand for output may result in an operating condition that initiallyand/or preferentially uses power from the battery, rather than the(cold) engine. In some cases, the demand may trigger a heating of anaftertreatment device associated with the engine. The battery mayprovide power (e.g., to a heater associated with the aftertreatmentdevice). The engine may be activated at or near a point at which theaftertreatment device is expected to perform (e.g., when theaftertreatment device reaches or approaches a temperature at whichemissions are reduced). The engine may recharge the battery.

Certain combinations of powertrain and demand for output may beassociated with “predetermined” optimized operating conditions. In suchcases, a hybrid powertrain may implement a predetermined operatingcondition without an optimization step.

FIG. 8 illustrates a method, according to some embodiments. In someimplementations, characteristic features of a duty cycle associated witha powertrain may be used to minimize the impact of emissions from thepowertrain. Characteristic features may include a type of equipment intowhich the powertrain is installed (e.g., a water pump, a garbage truck,a passenger vehicle, and the like). A duty cycle may include a demandfor output, and in some cases may include a temporal dependence of ademand for output. For example, a suburban letter carrier may drive avehicle that repeatedly accelerates away from a mailbox, travels to thenext mailbox, decelerates to the next mailbox, stops to deliver andretrieve mail, then repeats. A hybrid powertrain may use thisinformation to minimize emissions over the duty cycle. Minimization mayalso include location information. For example, a truck operating near aport or intermodal yard may be operated differently than a truckoperating in the countryside. A vehicle being driven at rush hour may beoperated differently than a vehicle driven at night. In some cases, therelative importance of certain pollutants vs. other pollutants changesas a function of time, place, and other aspects. CO2 emissions may bemore important in some cases. CO, soot, NOx, and the like may be moreimportant in other cases. A hybrid powertrain may be operated tominimize one or more pollutants, and may be adjusted to change therelative ratio of emitted pollutants according to various input factors.

In step 810 a system status is determined. System status may includecharacteristics of the powertrain, equipment driven by the powertrain,and input from sensors. Sensors may sense ambient parameters (e.g.,temperature, humidity), powertrain parameters (temperature, pressure,flow rate, output, and the like), load parameters (e.g., demand foroutput), and other parameters. In some embodiments, determining systemstatus includes retrieving stored values for one or more parameters.

Duty cycle history may be determined in optional step 820. In someimplementations, performance of a powertrain (e.g., emissions levels)may be affected by prior operation (e.g., a soot filter may become“clogged”). The duty cycle history may be associated with the past fewseconds, few minutes, few hours, few days, few weeks, few months, fewyears, or even longer times of operation. Duty cycle history may includecumulative information regarding various components (e.g., sootaccumulation in a particulate filter, reductant usage in an SCR system,time spent at temperature for an aftertreatment system, and the like).In some embodiments, a history of duty cycles (e.g., the past fewseconds, few minutes, few hours, few days, few weeks, few months, oreven longer) may be used to determine an optimal future operatingcondition. An estimated soot loading in a particulate filter may bedetermined (e.g., via duty cycle history, pressure differentialmeasurements before and after, and the like). In some aspects,determining the operating condition may include determining a time atwhich certain catalytic activity (e.g., NOx reduction, NOx trapping,soot lightoff, and the like) are expected, and may include minimizing atime needed to reach exhaust mitigation efficacy.

A request for output may be received in step 830. The request for outputmay be used to calculate an expected duty cycle that fulfills therequest. Duty cycle information associated with the calculated dutycycle may be stored.

In step 840, duty cycle information associated with the duty cycle maybe output. The duty cycle information may be associated with predictedoperating conditions over the next few milliseconds, few seconds, fewminutes, few hours, or even longer times of operation. Duty cycleinformation may be associated with an application of the engine (e.g.,bulldozer vs. combine harvester vs. tug boat vs. locomotive vs. backupgenerator) a day's work, a month's work, or even a year's work.

Duty cycle information may include a set of operating conditions for thepowertrain, and may provide instructions for controlling an engine, amotor, an energy storage device, an aftertreatment device, and/or othercomponents. An operating condition may include a regeneration protocolassociated with an aftertreatment device. In some cases, a predictedexhaust gas temperature profile (e.g., temperature vs. time) may be usedto determine a regeneration protocol for an aftertreatment device.

FIG. 9 illustrates a method, according to some embodiments. In step 910,an operating condition (e.g., a set of parameters associated withmeeting a demand for output) is received. An operating condition mayinclude a second operating condition that results in reduced emissionsas compared to a first or other operating condition. In step 920, acomponent may be activated. A component may include a motor, anaftertreatment device, a heater, a cooling system, an EGR system, aturbocharger, a valve, an injector, a vane (e.g., disposed in an exhauststream and/or intake stream) and the like.

In step 930, the engine may be controlled in a manner that reducesemissions. Component activation and engine control may take placesequentially (e.g., component first, then engine, or engine first, thencomponent). Component activation and engine control may take placesubstantially simultaneously (e.g., injection timing may be modified ina direct injection engine).

Duty cycle parameters (e.g., measures of an actual operating condition)may be recorded in step 940. In some cases, recorded parameters may bestored (e.g., integrated into a duty cycle history). In optional step950, one or more emissions may be monitored. Certain implementations mayinclude “closed loop” control of emissions. In such cases, parametersdescribing the monitored emissions may be incorporated into thecalculation of operating conditions (e.g., incorporated into a dutycycle history).

FIG. 10 illustrates an exemplary system, according to some embodiments.Certain locations are characterized by the periodic arrival of equipmenthaving relatively high levels of emissions. For example, an ambulancemay park at an entrance to a hospital and allow the engine to run whileunloading a passenger or waiting to load a passenger. A fire station mayhave fire engines that idle for extended periods of time outside thestation. A docked ship or boat may emit exhaust at the dock. A bus ortrain may sit with its engines idling. A tank or truck may operate at aservice center. In some cases (e.g., where engines repeatedly arrive atthe same location), a remote exhaust mitigation device may be disposedat the location, and an attachable/removable hose or conduit may beremovably coupled to the (exhaust emitting) tailpipe of the engine andused to convey exhaust gases to the remote mitigation device.

Remote aftertreatment system 1000 may be disposed in a location (e.g., ahospital) associated with a powertrain 1010 (e.g., an ambulance) thatemits exhaust. Exhaust may be emitted via tailpipe 1012. Emissions frompowertrain 1010 may be mitigated with an aftertreatment device 1020,which may be removably coupled (e.g., fluidically, electrically,mechanically, and the like) to powertrain 1010. In some cases, anattachable/removable fitting 1030 may couple to (or be disposed near)tailpipe 1012, and may carry exhaust gases from powertrain 1010 toaftertreatment device 1020 via hose 1040.

In some embodiments, aftertreatment device 1020 may include a fan 1050and/or other means (e.g., a pump, bellows, and the like) to “pull” gasesfrom tailpipe 1012 through hose 1040. In some cases, mechanicalattachment of fitting 1030 to tailpipe 1012 may not be necessary (e.g.,fitting 1030 may behave as a “hood”). In some cases, fitting 1030 maysealingly attach to tailpipe 1012. In an exemplary embodiment, fitting1030 may include an adjustable aperture (e.g., a plurality of extendable“leaves” as with a camera aperture) that may adjust to a range of radiiassociated with tailpipe 1012.

Aftertreatment device 1020 may include a system to mitigate one or morepollutants. In some embodiments, an aftertreatment device may include aDOC system, a soot filter, a de-NOx system, a catalytic converter, andthe like. An aftertreatment device may include a scrubber, an absorbingmaterial, an adsorbing material, and the like. Certain aftertreatmentdevices may include fly ash. An aftertreatment device may include acatalyst (e.g., disposed on a substrate). An aftertreatment device mayinclude a system 1070 to inject catalyst into the aftertreatment device(e.g., into an exhaust gas stream).

Aftertreatment device 1020 may include a cooling system (e.g., a waterspray). Aftertreatment device 1020 may include a heater 1022, which maybe configured to heat the exhaust gas and/or material contacting theexhaust gas. A heater may include a heating element (e.g., a glow plug),a catalytic combustor, a burner, and the like. Aftertreatment device1020 may be coupled to an energy source 1060. Energy source 1060 mayinclude an energy storage device (e.g., a battery, a fuel tank, and thelike). Energy source 1060 may include an electrical power line, anatural gas line, and the like. Energy source 1060 may provide energy to(inter alia) heater 1022. In some embodiments, heater 1022 includes aburner (e.g., with an ignitor), and energy source 1060 includes apropane tank. In some embodiments, energy source 1060 includes a powerline providing electrical power, and heater 1022 includes a heatingelement. Certain embodiments include a reformer coupled to a fuel sourceand configured to inject reformate into the system. Certain embodimentsmay be configured to inject an oxidizing species (e.g., oxygen, hydrogenperoxide, NO2, and the like) into the system. Some systems may beconfigured to inject a catalytic species (e.g., a liquid-carriedcatalyst) into the system.

In some cases, attachment of an emitting engine to an aftertreatmentdevice (or turning on an attached engine) may trigger an operation ofthe device (e.g., preheating the device, activating “suction” and thelike). In some cases, a flow rate (e.g., through the hose) may triggeractivation of the aftertreatment device. In some embodiments, a firstwireless signal is received (e.g., from an arriving ambulance). Thewireless signal may trigger a heater associated with the aftertreatmentdevice. A second wireless signal may trigger activation of suction. Insome embodiments, aftertreatment device 1020 may be disposed in anoverhead “bay” beneath which powertrain 1010 sits. In some cases, hose1040 may be disposed with a “boom” that provides for bringing fitting1030 close to (and/or in contact with) tailpipe 1012. In someembodiments, energy source 1060 may include a solar cell.

FIG. 11 illustrates an exemplary system, according to some embodiments.In some embodiments, an aftertreatment device may include a heater,which may be activated remotely. For example, an aftertreatment devicemay include a particulate filter such as a wall flow filter, a three waycatalytic converter, a lean NOx trap, an SCR device, a close coupledcatalytic converter, a diesel oxidation catalytic converter, and thelike. In some embodiments, a permeability (e.g., of exhaust gas) throughthe device may vary as a function of cross sectional area. In somecases, a first portion of the cross section of the device may have adifferent (e.g., higher) permeabilty (e.g., more open channels) than asecond portion. In some cases, a first or second portion is associatedwith a heater or ignition device (e.g., a glow plug, a burner, and thelike). In some cases, a portion configured to preferentially accumulatesoot particulates is disposed at an interior, and a heater is disposedwithin or adjacent to the portion.

Exemplary aftertreatment device 1100 may include a substrate 1110, andmay be disposed in an exhaust stream 1120. Substrate 1110 may include afirst portion 1130 having a first property, and a second portion 1140having a second property. Differences in properties may include adifferent catalyst, a different surface area, a different porosity, adifferent mean or median pore size, a different permeability, adifferent thermal expansion coefficient, a different heat capacity, adifferent thermal conductivity, a different crystal structure, adifferent amount of amorphous phase, a different chemical composition,and the like. In some embodiments, heater 1022 may be disposed in afirst portion, and in certain cases a portion having a heater may have ahigher permeability than another portion. In some embodiments, heater1022 may be activated remotely (e.g., prior to passage of exhaust gas).In some implementations, a flow of exhaust gas activates heater 1022.Heater 1022 may be disposed toward an “interior” of substrate 1110 or an“exterior” of substrate 1110 (e.g., wrapped around). Heater 1022 may bedisposed toward an “upstream” portion, a “downstream” portion, or a“middle” portion (with respect to exhaust flow).

In some methods, a heater or other device (e.g., associated with anexhaust aftertreatment system) may be activated prior to or in concertwith activation of an engine. A temperature (or other parametercharacterizing efficacy) associated with an exhaust aftertreatmentsystem may be determined and/or may be monitored. An activation timeassociated with activating an engine coupled to the aftertreatmentsystem may be determined (e.g., calculated). An activation time may be atime after which an aftertreatment system is expected to be effective(e.g., have an effective temperature, have a temperature at whichlightoff may be triggered, and the like). In some embodiments, anaftertreatment system is “heated” prior to or in concert with passage ofexhaust gas passage, and so may reach an operation temperature (e.g., bealready “warm”) faster than a non-hybrid system.

In some embodiments, an aftertreatment system may include a poroussubstrate. The porous substrate may have a volume greater than onegallon, greater than 50 gallons, greater than 100 gallons, greater than500 gallons, or even greater than 1000 gallons. Some substrates may beapproximately the size of a refuse dumpster and/or a shipping container.In some embodiments, a heater may be disposed at an interior of asubstrate from which heat transfers relatively slowly. A heater may besubstantially “constantly” heated (e.g., with a pilot light or lowcurrent element) such that a first portion of the substrate remains“warm” (e.g., above 50 C, above 100C, above 200C, above 400C, and thelike). In some cases, the first region may be a region having apermeability that results in a preferential flow of exhaust gas throughthe first region.

The above description is illustrative and not restrictive. Manyvariations of the invention will become apparent to those of skill inthe art upon review of this disclosure. The scope of the inventionshould, therefore, be determined not with reference to the abovedescription, but instead should be determined with reference to theappended claims along with their full scope of equivalents.

1. A powertrain comprising: an engine; a motor; an axle configured to becoupled to a load; the engine, motor, and axle coupled such that acombination of engine output and motor output may be delivered to theload; a power source coupled to the motor; and a powertrain control unitcoupled to the engine, motor, and power source, the powertrain controlunit configured to receive a demand for output to be provided to theload and determine an operating condition comprising a combination ofengine output and motor output that fulfills the demand, the powertraincontrol unit including a processor and coupled to a computer readablestorage medium having embodied thereon a program executable by theprocessor to perform a method comprising: receiving a demand for outputto be provided to the load; predicting a first emissions profile thatwould result from fulfilling the demand under a first operatingcondition, the first emissions profile characterizing one or morecriteria pollutants in an exhaust stream from the engine duringoperation according to the first operating condition; predicting asecond emissions profile that would result from fulfilling the demandunder a second operating condition, the second emissions profile havinga reduced amount of at least one criteria pollutant as compared to thefirst emissions profile; and controlling the motor and engine to fulfillthe demand according to the second operating condition.
 2. Thepowertrain of claim 1, wherein the second emissions profile has anincreased amount of CO2 as compared to the first emissions profile. 3.The powertrain of claim 1, wherein the reduced amount of the criteriapollutant in the second emissions profile includes at least one of soot,NOx, a hydrocarbon, NH3, and CO, and the second emissions profileincludes an increased amount of at least one other of soot, NOx, ahydrocarbon, NH3, and CO, as compared to the first emissions profile. 4.The powertrain of claim 1, wherein: the combination of engine output andmotor output according to the second operating condition has a largerportion of the output provided by the motor than does the combinationaccording to the first operating condition.
 5. The powertrain of claim1, wherein determining the first and second emissions profiles includes:receiving duty cycle information associated with the demand; and usingthe duty cycle information to determine the second operating condition.6. The powertrain of claim 5, wherein the duty cycle informationincludes a history of operating conditions used to fulfill priordemands.
 7. The powertrain of claim 1, further comprising: measuring atleast one value of a parameter associated with the exhaust stream underthe second operating condition; calculating a first expected value ofthe parameter under the second operating condition; determining a firstdifference between the measured and first expected values; predicting athird emissions profile associated with fulfilling the demand under athird operating condition, calculating a second expected value of theparameter under the third operating condition; determining a seconddifference between the measured and second expected values, the seconddifference lower than the first difference; and fulfilling the demandaccording to the third operating condition.
 8. The powertrain of claim7, wherein predicting the third emissions profile includes using apreviously recorded difference between the measured and expected valuesof the parameter during a previous operation of the powertrain.
 9. Thepowertrain of claim 5, wherein the duty cycle information includes ageographical location at which the powertrain fulfills the demand foroutput.
 10. The powertrain of claim 5, wherein the duty cycleinformation includes a type of equipment associated with the load. 11.The powertrain of claim 5, wherein the duty cycle information includes aset of expected future demands.
 12. The powertrain of claim 5, whereinthe duty cycle information includes fuel information.
 13. The powertrainof claim 5, wherein the duty cycle information includes a time.
 14. Thepowertrain of claim 1, further comprising an aftertreatment system influidic communication with the engine and configured to treat theexhaust stream, the aftertreatment system coupled to the powertraincontrol unit and the power source, wherein the second operatingcondition includes: activating the aftertreatment system with the powersource prior to delivering engine output to the load; and fulfilling thedemand using the motor until the aftertreatment system is activated. 15.The powertrain of claim 14, wherein activating includes heating theaftertreatment system.
 16. The powertrain of claim 14, wherein thesecond operating condition includes delaying a fulfillment of the demanduntil the aftertreatment system is activated.
 17. The powertrain ofclaim 14, further comprising a sensor coupled to the aftertreatmentsystem and the powertrain control unit, the sensor configured to sensewhen the aftertreatment system has been activated.
 18. The powertrain ofclaim 1, wherein the power source includes a supply of electricityderived from an electrical grid.
 19. The method of claim 2, wherein theemissions profiles include an integrated global warming potentialcharacterizing the aggregate effect of all species in the exhauststream, and the second emissions profile has a lower integrated globalwarming potential than does the first emissions profile.